Piston expander



Dec. 28, 1937. D, M, SMITH 2,103,664

' PISTON EXPANDER Filed March 25, 1937 1mm Mn III DHLLAS M. SMITH www;

Patented Dec. 28, 1937 I 2,103,664

UNITED STATES PATENT OFFICE PISTON EXPANDER. Dallas M. Smith, Kirkwood, Mo.

Application March 25, 1937, Serial No. 133,053

6 Claims. (01. 309-12) My invention relates to piston expanders and wrist pin G on which is mounted the upper end more particularly to piston expanders as used of the connecting. rod H. in internal combustion engines to increase the In this embodiment the expander proper conefiective diameter of the piston skirt whereby sists of a U-shaped member J having fiat ends compensation. may be made for wear between J adapted to engage the inner surface of the 5 the piston and the cylinder in which it recipropiston skirt at diametrically opposed points recates. moved approximately ninety degrees from the Heretofore, although it has been comparatively bosses F, as shown in Fig. 3. The member J is simple to insert a resilient or spring member in formed and arranged so that the upper portion the piston to increase the diameter of the skirt, thereof extends above the pin G and the upper 10 it has been difiicult to provide means whereby end of the connecting rod H. Extending downthe expander would be maintained in fixed prewardly from the upper portion of the member J determined position during operation of the moand, preferably, formed integral therewith are tor. The piston skirts as now used are in reality a pair of parts K each having its lower end ar- 15 resilient split bands and the forces generated ranged with a arcuate shaped notch L adapted 15 by the extremely rapid movement of the piston to engage the upper surface of a boss F. Exin the cylinder often cause the skirt to go into a tending upwardly from the member J and seflutter or tuned vibration. Since the expander cured thereto by any suitable expedient, as by is acting upon the skirt, it also may vibrate at a rivet M, is a spring N arranged to engage, in a high frequency and, therefore, unless the exthis embodiment, the inner surface of the top 20 pander is securely anchored to the piston it may of the piston and to create a tension to force the become dislodged from its position therein and lower ends of the parts K firmly against the pin drop into the moving parts of the motor. bosses so that the expander will be maintained With this problem in mind the objects of my in place securely within the piston. invention are to provide a piston expander which As implied above, the portion of the expander 25 includes parts whereby the expander may be ancomprising the member J and parts K, preferchored securely inside of the piston and. to proably, is stamped as a single piece of spring steel vide a piston expander which will be simple in of proper gauge and hardness. The tension design, cheap to manufacture and efficient in spring N may be a separate piece, as shown in operation. this embodiment, or in other embodiments 30 My invention in its broadest aspect contemtongues may be stamped out of the member J plates the use of an expander having a member and bent upwardly to form the spring. Also, of arranged to engage and expand the piston skirt, course, the parts K may be positioned and adaptand, also, having parts engaging the interior of ed to engage knobs formed on the piston skirt the piston, preferably, in the pin bosses, and or other protuberances on the inner surfaces of 35 provided with. a spring adapted to create a tenthe piston. In any event, the spring N will hold sion to hold the parts securely in place. the lower ends of the parts K firmly in their A simple embodiment of the expander embodyplace of engagement. s th s inv s s wn n th a ompanyin When the expander in the embodiment shown 40 drawing wherein similar characters .are used to is to be inserted in place in the interior of a 40 designate similar parts. In the drawing, Fig. 1 piston the skirt engaging ends J of the memis a view of a piston, partially broken away, and ber J preferably are tied together by a wire or its included expander made according to my new held in collapsed position by other suitable exand improved design; Fig. 2 is a bottom view pedient and the expander is inserted upwardly of the assembly shown in Fig. 1; Fig. 3 is a secin the piston from the open bottom of the skirt. 45 tion along the line 33 in Fig. 2; and Fig. 4 is When the parts K come into engagement with a view of the expander removed from the piston. the pin bosses movement of the expander into Referring to the figures the piston A on which the piston will collapse these parts and then the expander is assembled has a head B and a when the lower ends L of the parts have moved I skirt C separated therefrom throughout a major past the inner faces of the bosses the parts will 50 portion of its periphery by circumferentially exspring outwardly so that the ends will engage tending slots D. The skirt C also is split axially the upper portions of the bosses, as shown in Fig. as at E so that in effect the skirt is a resilient, 1. As stated before, firm engagement between split band. The piston is provided with bosses the ends L and the bosses will be maintained by F of usual design and through which extend a tension of the spring N. I 55 I have shown and described a simple embodiment of my invention in the specification and drawing herein, however, I do not propose to limit myself to the form shown or to any other form because construction of an expander embodying my new and improved design may be varied in size, shape and arrangement of the various parts and their relation to one another may be changed within wide limits without deviating from the ambit of the appended claims.

What I claim as new and desire to secure by Letters Patent, is:-

,1. A piston expander comprising a, member arranged to engage and expand the skirt of a piston, a pair of additional parts carried by said member and positioned to engage interior portions of the piston at opposed points and a spring carried by said expander to engage the head of said piston and to exert a tension to hold said parts firmly at their place of engagement.

2. A piston expander comprising a Ushaped member having a. pair of legs adapted to engage and expand the skirt of a piston at substantially diametrically opposed points, a pair of additional parts carried by said member at the top thereof and positioned to engage interior portions of the piston, and a spring carried by said member to engage the head of said piston to exert a tension to hold said parts firmly at their place of engagement.

3. A piston expander comprising a member arranged to engage and expand the skirt of said piston, a pair of parts carried by said member and positioned to engage the upper surfaces of the pin bosses of said piston and spring means carried by said expander to engage the top of said piston and exert a tension to hold said parts in firm engagement with said pin bosses.

4. A piston expander comprising a member arranged to engage and expand the skirt of said piston, a pair of resilient parts formed and positioned to engage the upper surfaces of the pin bosses of said piston and spring means carried by said expander to engage the head of said piston whereby said parts will be held in firm engagement with said pin bosses.

5. A piston expander comprising a U-shaped member arranged to engage and expand the skirt of a piston at substantially diametrically opposed points, said member extending across the hollow interior of the piston above the pin bosses thereof, a pair of parts carried by said member and positioned to engage the upper surfaces of said pin bosses, and a spring extending upwardly from said member to engage the head of said piston and exert a tension to hold said parts in firm engagement with said pin bosses.

6. A piston expander comprising a U-shaped member arranged to engage and expand the skirt of a piston at substantially diametrically opposed points, said member extending across the hollow interior of the piston above the pin bosses thereof, a pair of parts formed integral with said member and extending downwardly from the upper portion thereof and positioned so that the lower end of each of said parts engages the upper surfaces of one of said pin bosses, and a spring extending upwardly from said member to engage the head of said piston and exert a tension to hold the lower ends of said parts in firm engagement with said pin bosses.

' DALLAS M. SMITH. 

